Electric heater.



No. 674,I24. Patented May l4, mm. c. ROBINSON.

ELECTRIC HEATER.

(Application filed Apr. 17, 1899.)

(No Model.)

IN VENTOH W/ TNE SSE S Tn: mu men ea, mmu'mc" WAINIW. n. c.;

UNITED STATES PATENT OFFICE.

CONWAY ROBINSON, OF BALTIMORE, MARYLAND.

ELECTRIC HEATER.

SPEGIFICATION forming part of Letters Patent No. 674,124, dated May 14,1901.

Application filed April 17, 1899.

To all whom it may concern.-

Be it known that I, CONWAY ROBINSON, a citizen of the United States,residing at Baltimore city, in the State of Maryland, have inventedcertain new and useful Improvements in Electric Heaters, of which thefollowing is a specification.

The object of my said invention is to produce an apparatus for heatingby means of electricity, especially where high temperatures arerequired; and it mainly consists of an inclosed electric are formed bymeans of a carbon or other ordinary electrode and an elec trode formedfrom metal or other good conductor of heat, the latter being preferablyclosely joined to or formed integrally with a part or parts by which theheat is to be conducted to the article to be heated in connection withsurrounding heat-insulating substances, the whole being contained in acover or shell of suitable form and material. In this apparatus themetal or heat-conducting electrode should be cup-shaped and inclose thearc and a considerable portion of the end of the carbon electrode in.such manner as to absorb and utilize the heat generated by the arc.

An apparatus embodying said invention will be fully de'scribed,and thenovel features sist in the surrounding of an inclosed electric are moreor less completely with a good heatconducting materiahprefe'rablycopper,which material forms oneof the electrodes of the are, preferablythe positive, when a higher efficiency is required. This electrode isclosely attached to or formed integrally with a part which issubstantially a prolongation thereof, and which is soshaped as tosurround or cover more or less completely or lie next to the Serial No.713,312. (No model.)

piece or pieces to be heated. The whole apparatus is efficientlyinsulated by covering or surrounding the hot parts by a heat-insulatingsubstance or substances. The covering of the cup in which the arc isformed should be removable, and the whole is contained within a suitableshell. Any desired means may be provided for feeding the movableelectrode, either automatically, mechanically, or by hand.

In the drawings the portions marked A represent the outer shell orcovering for the apparatus, which may be conveniently and efficientlyformed of cast-iron. This is mounted upon a base B, in which I haveplaced proper resistance-coils C for controlling the electric currentand a switch S for throwing the current on and off. In the apparatusshown, which, as above stated, is designed specially for heatingsolderingirons, there is an opening into one side of the shell A, whichin the construction shown has a mouth in the form of an inwardlyextending flange (1. Connected to this flange is the part D, by whichthe heat is immediately conducted to the article to be heated and whichin the con-, struction shown is formed integrally with the cup-shapedmetal electrode This part D is in the form of a tube and into it thesoldering-iron or other article to be heated is inserted when theheating is to be done. It is connected to the flange a by means ofsuitable bolts d, which bolts, as well as the flange a,are carefully andcompletely insulated from the part D by insulating material F,interposed between the parts ct and d and surrounding and lying underthe heads of the bolts and those portions which would otherwise come incontact with the metal of said flange, so that said part D is completelyinsulated from the metal of the surrounding shell.

The metal electrode E is preferably, as is clearly shown, of a deep cupshaped formation, the are being formed in the cup and being thuscompletely surrounded by the highlyconductive metal of this electrode.Resting upon and covering the cup of this electrode is thenon-conducting cap or cover .G, through a perforation in the centerwhereof the carbon Hextends down into the cavity of the part E.- Inorder that this opening may be more tightly closed than is otherwisepracticable, I use the small block g of fireproof material, which neatlyfits around the carbon and may slide horizontally over the cap G, so asto prevent the entrance of air into the chamber and at the same time notbind the carbon or prevent it from moving freely. Above the part G, Iprefer to place two other corresponding parts G and G and surroundingthe whole is, an insulating-cylinder I. These several parts G, g, G, Gand I are all preferably formed of fire-clay or similar insulating andheat-resisting substance. Secured above these parts is a metal plate J,which forms the base of the framework for the feed mechanism, and thisis insulated from the lower parts by means of the ashestos or otherinsulating plate K.

Surrounding the carbon H is a soft-iron core L, which is supplied with agland Z to hold the carbon from slipping through, but

still allow it to be pushed down when required. This core is operated bya solenoid M, operating in a well known manner. Alongside the solenoidare two dash-pots N N, connected by a bar N, which serve, as is wellknown, to prevent a sudden or jerky motion of the armaturewhen thecurrent is turned on or when the arc is formed. The cylinders of thesedash-pots are carried on the tubing T, which in turn is supported by thearmature L. The pistons O of the dashpots are carried from asuitablecross-bar on the frame, as shown.

The electric connections will be understood by an examination of Figs. 2and 4. In operation when the current is turned on the armature L and thecarbon H are lifted and an arc is formed between said carbon and theadjacent portion of the wall of the chamber formed in'the cup-shapedmetallic electrode. As very little heat can pass the insulatingblocks G,g, G, and G it is practically all abs'orbed by the copper cylinder E andgiven out therefrom only'through its inside walls, as the outside wallsare protected from the loss of heat by the insulating substance F, bywhich it is kept from contact with the outer shell, and theinsulating-packing P, which is inserted in the'outer shell, filling thespace between it andthe inner parts, as shown.

The arc being inclosed' prevents loss of heat by air-currents andenables'a longer are to be maintained than would be the case if it wereexposed to the air, and for this reason there less resistance in serieswith the arc, and consequently allows a greater proportion of the.operating feed mechanism therefor, a good heat-conductive electrodehaving an extension for receiving the article to be heated, means forsupporting the same within a surrounding shell, said shell, andheat-insulating material Within said shell and surrounding andinsulating said heat conductive electrode, substantially as and for thepurposes set'forth.

2. The combination, in an electric heater, of a shell having an openingtherein, a'heat conducting and transmitting part secured within saidshell near said opening but heatinsulated therefrom, a cup-shapedelectrode connected to or forming a part of the same, an ordinaryelectrode extending into said cupshaped electrode, anautomatically-operating feed mechanism therefor, and insulating coveringdevices covering the chamber formed in said cup-shaped electrode,whereby the heat generated by the electric arc is confined in saidchamber and transmitted therefrom through said electrode andits'connected parts, substantially as set forth.

3. The combination, in an electric heater, of an outside shell formechanical protection having an opening therethrough leading to theworking parts of the apparatus, a good heat-conductor adjacentto theopening in said shell and carried therefrom, insulating materialinterposed between said good heatconductor and said shell, a cup-shapedelectrode connected to or formed integrally with said goodheat-conductor, an ordinary electrode extending into said cup-shapedelectrode, insulating-covers for the chamber formed thereby, and meansfor operating an electrode to form an electric are, substantially as andfor the purposes set forth. J '4'. The combination, in an electricheater, of an outer shell or casing, a heater-body composed of goodheat-conductive material'termimating in an electrode and containedwithinsaid outer shell or casing and supported thereby, heat and electricalinsulating material interposed between said heater-bodyand said outercasing where they are united, a removable electrode the inner endwhereof approaches the electrode carried by the heater-'- b'ody,automatical-ly-operating means for operating thesame', suitable heat andelectrical insulating material surrounding said lastnamedelectrode andcovering the chamber in which the arc is formed, and suitable electricalconnections connecting said electrodes, said heater b'ody being hollowand adapted to receive the article or material to be heated. 5. Thecombination, in an electrical heater, of an outershell or casing havingopenings in its top and side, a suitable base therefor, a heater-bodyterminating in a cup-shaped electrode and supported from said outershell or casing adjacent to the opening therein, insulating materialinterposed in the joint between the heater-body and the shell or casing,a cylindrical part extending upwardly from the heater-body to the'upperopening in the shell or casing, perforated caps composed of refractoryand insulating material occupying the upper portion of said cylinder, anelectrode perpendicularly positioned and extending down through. theperforations in said caps, an electrical connection extending to saidelectrode, means for operating said elec trode to form the arc, and anelectrical connection extending to the lower cup-shaped electrode, saidlast-named connection having resistance interposed therein, saidheaterbody being hollow to receive the article to be heated,substantially as shown and described.

6. In an electric heater, the combination of a heater-body, a shell orcasing surrounding the same with an opening extending through the shellor casing to the inside of the heaterbody, said heater-body supportedfrom the shell or casing near said opening but electrically and heatinsulated therefrom, electrical and heat insulating material surroundingthe heater-body between the heater-body and the outside shell or casing,an electrode adj ustable toward and from said heater-body to form an arcthe hotter portion of which is partly surrounded by the heater-body, anautomatically-operating feed mechanism therefor, a cylinder-ofinsulating and refractory material extending through the insulatingsubstance inside the shell or casing and giving access to the electrodeportion of the heaterbody, and insulating and refractory pieces coveringsaid electrode portion and located inside of the cylinder.

7. The combination, in an electric heater, of a metallic heater-bodyforming a good heatconducting electrode and having a chamber thereinadapted to receive the article to be heated through an appropriateopening, another electrode mounted to be movable toward and from theheater-body electrode, insulating material surrounding said heaterbodyelectrode provided with an opening for the entrance ofsaid movableelectrode, suitable electrical connections with said two electrodes, andmeans for operatingsaid movable electrode to form an are, substantiallyas set forth.

8. The combination, in an electric heater, of an outside shell having anopening therein leading to the working parts of the apparatus, a goodheat-conductor arranged Within said shell adjacent to the openingtherein and carried therefrom,insulating material interposed betweensaid good heat-conductor and said shell, a good heat-conductiveelectrode connected to or formed integrally with said heatsconductor,"an ordinary electrode extending into proximity with said goodheat-conduct ive electrode, and means for operating said electrode toform an electric arc.

In witness whereof I have hereunto set my hand and seal, atIndianapolis, Indiana, this 25th day of March, A. D. 1899.

CONWAY ROBINSON. [L. s.]

Witnesses:

JAMES A. WALSH, v C. S. FRYE.

